In the past, changeable signs and other information display devices and systems have sometimes been made up of multiple major components which, in themselves, are also made up of smaller components, such as incandescent electric lamp associated in modules and selectively activated, by switching means, to present intelligible characters or symbols. For purposes of the present invention, those visible elements which, in the composite, make up the information to be displayed, will be referred to as "luminous", whereas the blanks, or unlighted or relatively invisible areas between will be referred to as "non-luminous", as a matter of convenience. That is, a surface, component or element of the sign which contributes in a visual aspect to the information being displayed will be considered "luminous" whether it actually gives off light (as in the case of an incandescent lamp bulb) or merely reflects light from some other source, as in the case of a white or light colored area which is more visible than the surrounding background. In the case of dark colored display characters, such as black or other dark colored letters on a white or other light colored background, the term luminous will be understood as referring to the character defining part, and not to the background, regardless of the actual amount of light emanated or reflected.
In the past, the individual modules of signs, such as those used for displaying time and/or temperature data, information signs along major highways and streets giving traffic information or directions, etc., have commonly beem made up by mounting rows and/or columns of electric lamps, to be lighted up selectively as the information to be displayed changes. Such lamps, usually incandescent light bulbs, are often selectively lighted by complex and remotely controlled switching means to display in each module a particular symbol, such as a letter of the alphabet or an arabic numeral. The composite sign, consisting of multiple modules, is lighted up by activating the appropriate elements in all the modules, all that are needed, to display the desired information.
As a rule, in signs of this general nature, the elements in each module usually are arranged so that any one, but only one, discrete character or symbol may be displayed by that module. Hence it requires as many modules as there are characters to be displayed in a typical prior art sign. One aspect of the present invention is the arrangement of elements in a module so that, if desired, more than one symbol or character, or component of information may be displayed by a single module, although in many applications, each module may be used to display only one character or symbol. In certain other applications, a single character or symbol may be displayed by a plurality of adjoining modules.
By thus activating selected elements in the various modules, the information may be changed from time to time, as needed, both in the prior art devices and in the present invention.
Some signs do not include self-lighted elements, such as incandescent lamps, but may depend on reflection of light from external sources to display the desired information. Such external sources may be sunlight, artificial light from various locations, such as from the headlights of automobiles on a highway, etc., as is well known. It has been proposed in the past to mount rotatable or otherwise shiftable parts in the modules, so that a relatively visible face or surface, one that is luminous by the above definition, can be displayed or, alternatively, to show the non-luminous reverse face or surface so as to in effect black out that particular element or blend it into the background so that it is not noticeable. With energy shortages existing and threatened, there is much need to conserve electric power and such usage of reflective elements and components to replace incandescent lamps and the like is bound to increase. Numerous proposals have been made in recent years for using shiftable elements in signs, so that one face or surface of an element is visible or "luminous" and another is relatively invisible or "non-luminous". Selectively turning or shifting of the component which bears these faces or aspects has been provided for by earlier investigators. For example, a recent publication (Feb., 1975) by Finnan Engineered Products, of Scarsborough, Ontario, Canada, and "Time-O-Matic", of Danville, Ill., described modules made up of rotatable discs each having a bright or visible face and a dark, relatively invisible face, to be shifted by remote control, using "solid state electronics". The present invention, and that described in the parent copending application, mentioned above, is similar in some respects. Other and related proposals have been made, e.g., in the Christian Science Monitor, Apr. 19, 1973, which mentioned rotatable visual elements that are shifted by computer control to present relatively visible and invisible or luminous and non-luminous aspects. See also, "Signs of the Times," Oct. 1974, pp. 48-50.
Parent application, Ser. No. 576,127, mentioned above, now U.S. Pat. No. 4,006,476 describes a display system wherein plural modules are set up to form a composite sign. Each module is made up of rotatable, reversible elements, operated electromagnetically, to display selectively a highly visible side or face and a relatively invisible or background blending face. The application describes the use of simple, easily controlled and actuated electromagnetic means to shift the rotatable elements from one aspect to the other. Similar means are a part of the present invention but the present case goes farther in providing for substitution of self-lighted components for the reflective type when needed, as frequently is the case. Thus, an important feature of the present invention is the means and method by which a sign may be easily and rapidly converted from a reflective type to an incandescent or self-lighted type and vice versa, with minimal extra parts, securing means, conductors, etc.
Another important object of the present invention is to adapt it to convenient and effective remote control, whether self lighted or reflective light elements are used, with low consumption of electric power, by reason of the manner in which the movable parts, or the lights, are energized. Design of the circuitry and the elements that comprise the power circuit is one aspect of this objective. Prior art devices of the general types mentioned above, so far as information about them is available to the present inventor, apparently are controlled by relatively complex means and the component parts used are relatively much more costly.
The present invention includes a number of other features not found in the prior art and offers many advantages, including simplicity and interchangeability of parts, compactness of assembly, versatility of relatively few mounting parts, especially fastening means, for various functions, and the combining of multiple functions in some of these components. A strong, rigid sign structure is obtained, capable of easy and rapid assembly. The display elements themselves are readily transformed from self-luminous to reflective types or vice versa, making it possible to use external light sources to a maximum while permitting easy conversion to self-lighting when needed. Using a base supporting structure, large components embodying a group of modules in each are assembled to form a continuous or essentially continuous surface, usually arranged in a display plane but adabtable to curved, double curved or other display areas. Each module has its own base and its own circuitry, preferably a printed circuit. Each element has its own housing, made preferably in two identical and interchangeable parts. The larger, multiple module units, which may be called sub-assemblies, have also their own base and/or circuitry, preferably printed circuits also, and still larger units, made up of groups of sub-assemblies, may readily be composed, for the largest display systems, using the same or similar connecting, fastening and current-conducting components which, to a large degree are interchangeable and multifunctional. Some of the components have novelty in themselves and are designed to be adaptable to various uses, not only in the present system but in other apparatus of various kinds. These are another aspect of the present invention.
In its method aspects, the invention comprises a method of displaying information over a generally continuous display area by arranging in modules pluralities or groups of individually convertible elements in rows and/or in columns which may be either self-lighted or lighted by reflected light from other sources and which may, in either case, be selectively and individually turned on or off, either by switching electric current on or off or by switching the position of the element itself from active or luminous to inactive or non-luminous position. The modules, in turn, are also arranged in groups, which may be either rows or columns, or both, in contiguous or essentially contiguous relationship, to give a generally continuous display surface over larger areas. The individual modules, through their own local or satellite, circuitry (printed circuit, preferably) are directly connected to a master circuit through means which simultaneously provide appropriate spacing between the local circuitry of the module and the more general circuitry of the master board or circuit. The latter, in turn, may be connected to a still more general power and control system for larger area displays, using similar components, as already suggested.
Further aspects of the invention, along with particular advantages and special objectives that are obtained, will appear from the detailed description which follows.